The special insurance document will provide confirmation that a vehicle from the UK is insured in the EU. After the end of the transition period, from January 1, the so-called green card will be needed by UK passengers traveling into the EU unless a new system is agreed on during the Brexit negotiations.
The plans set in place so far will keep the border between Northern Ireland and the Republic of Ireland open.
But concerns have been raised that the green card system will be costly.
John Martin, policy manager at the Road Haulage Association in Northern Ireland said: “This is just another layer of bureaucracy if introduced, albeit feedback from some of the insurance sector says that insurance certificates already have this green card provision already included.
“If insurance companies begin to start charging operators for this, and if there is a limit on the duration of the green cards, then that adds to the burden hauliers are already facing as a consequence of Brexit.”
The Irish government have said the green card system is likely to be the first of many changes post-Brexit.
Thomas Byrne, Irish Minister for EU Affairs, said: “Brexit will also bring changes, many of which, most of us don’t want.
“Unfortunately, those changes are going to be difficult for people on both sides of the border.
“On the issue of the green card for insurance, that is currently a requirement of the European Commission for cars coming from outside the European Union.
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Irish drivers crossing the border into Northern Ireland will not be required to have a green card.
But Northern Ireland drivers travelling the other way will be required.
An Irish Department of Transport spokesperson said: “A green card is a document issued by your insurer that proves you have motor insurance cover when driving in another jurisdiction.
“As it stands, following the transition period, a green card will be required for vehicles from the UK, including Northern Ireland, being driven in Ireland or other EU Member States, unless the European Commission declares otherwise.”
The Department for the Economy has estimated that there are approximately 110 million border crossings between Northern Ireland and the Republic of Ireland each year.
The green card system may not be required if the UK and EU resolve the matter during their negotiations for a post-Brexit deal.
But the EU chief negotiator Michel Barnier said a deal looked “at this point unlikely” due to the UK’s position on competition rules and fishing rights.
The UK counterpart, David Frost said “considerable gaps” remain in these areas.
Mr Frost believes, however, that a deal is still possible.
Another round of official talks between the UK and EU is scheduled in Brussels for mid-August.